Re: Sybase Connection - trouble without protocol fallback

Hi, Fredy,

On Tue, Jul 4, 2017 at 9:15 AM, Fredy Paquet <[email protected]> wrote:
> Hello Frediano
>
> Thank you for the fix of the encryption flag in the login packet.
> (I will verify correct operation next saturday)
>
> What can we do about the fallback problem (see below) ?
>
> --- Proposal 1
>
> Change the statment to use TDS_ENCRYPTION_OFF:
>
>   if (login->encryption_level == TDS_ENCRYPTION_DEFAULT)
>     login->encryption_level = TDS_ENCRYPTION_OFF;
>
> Because default encryption level is defined as OFF.

What if the encryption becomes ON?
How do you differentiate between them?

Maybe we need to introduce something like DEFAULT for the encryption
the configuration file?

>
> --- Proposal 2
>
> I propose using a temporary local variable  for the tds71-try,
> instead of modifying an entry in the login record, which is being
> used later for other protocol tries.
>
> in function tds71_do_login():
>
> TDS_TINYINT my_encryption_level
>   = (login->encryption_level == TDS_ENCRYPTION_DEFAULT)
>     ? TDS_ENCRYPTION_REQUEST : login->encryption_level;
>
> then try with locally with my_encryption_level
>
> (this may be combined with Proposal 1)
>
> --- Proposal 3
>
> Drop the whole statement, because encryption_level should be controlled
> by a freetds.conf setting. But on the other side, this might kill
> working freetds.conf configurations.

Probably not a good idea.

Thank you.

>
> What do you think about it ?
>
> fp
>
> On Wed, 2017-06-28 at 09:12 +0200, Fredy Paquet wrote:
>>
>> This is due to the fact that in login.c(Line 1128) in function
>> tds71_do_login() the encryption level is set to REQUEST, but never
>> reset
>> again:
>>
>>         if (login->encryption_level == TDS_ENCRYPTION_DEFAULT)
>>                 login->encryption_level = TDS_ENCRYPTION_REQUEST;
>>
>> This could easily fixed by saving/restoring the encryption level, but
>> i'm asking me whether if there are other modified fields not being
>> restored properly. The protocol fallback loop is in login.c Line 404.
>
> --
> Fredy Paquet
> Mitglied der Geschäftsleitung
> OPAG Informatik AG
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>
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